1. Technical Field
The present invention relates to a screen.
2. Related Art
To date, various kinds of screen have been proposed, each of which includes a sheet-like screen main body having flexibility, wherein an image light projected and magnified from a projector or the like is projected onto a projection surface of the screen main body.
With this kind of screen, as the sheet-like screen main body is employed, it is necessary to suppress a deflection and undulation of the screen main body, and maintain the flatness of the projection surface. Therein, the following technology has heretofore been proposed which suppresses a deflection and undulation of the screen main body (for example, refer to JP-A-4-264436).
A screen described in JP-A-4-264436 is configured of a screen (hereafter described as a stationary screen) in which a projection surface is always formed in a condition in which a pair of opposed edges of a screen main body is supported. More specifically, the screen described in JP-A-4-264436 includes a fixed edge and movable edge which each support one of the two up-down (vertical) direction edges of the screen main body, a tension application mechanism which moves the movable edge, changing the up-down direction tension of the screen main body, a sensor which detects a change in tension of the screen main body, and a drive control circuit which controls the tension application mechanism in accordance with an output of the sensor. By means of this kind of configuration, tension is applied to the screen main body in an up-down direction, suppressing a deflection and undulation of the screen main body.
However, with the technology described in JP-A-4-264436, although both up-down direction edges of the screen main body are fixed, as the screen is in a condition in which both left-right (horizontal) direction edges of the screen main body are released, it is impossible to prevent a deflection and undulation of both left-right direction edges. That is, there is a problem in that it is impossible to efficiently maintain the flatness of the projection surface.
Also, with the technology described in JP-A-4-264436, as the screen is configured as a stationary screen, the screen is in a condition in which the projection surface is formed even when the screen is not used, so there is a problem in that the screen is difficult to carry about.